/Engine/Source/Runtime/Engine/Classes/Engine/NetDriver.h
This does not change the Actor's actual NetDormant state. If a dormant actor is Flushed, it will net update at least one more time, and then go back to dormant.
void FlushActorDormancy ( [AActor](API\Runtime\Engine\GameFramework\AActor) * Actor, bool bWasDormInitial )